This application claims, under 35 USC 119, priority of Japanese Application No. 2001-155747 filed May 24, 2001 and Japanese Application No. 2002-54810 filed Feb. 28, 2002.
1. Field of the Invention
The present invention relates to a shielding base member and a method of manufacturing the same and, more particularly, a shielding base member for shielding from electromagnetic radiation, etc., that leak out from the PDP (Plasma Display Panel), etc. and a method of manufacturing the same.
2. Description of the Related Art
In recent years, the applications of the PDP (Plasma Display Panel), which has a wide viewing angle and good display quality and provides a large screen, have broadened quickly into multimedia display devices, etc.
The PDP is a display device that utilizes a gaseous discharge. The gas that is sealed in the tube is excited by using the discharge to generate a line spectrum that has a wide wavelength range extending from the ultraviolet range to the near-infrared range. A fluorescent substance is arranged in the tube of the PDP. This fluorescent substance is excited by the line spectrum in the ultraviolet range to generate light in the visible range. A part of the line spectrum in the near-infrared range is emitted from the surface glass of the PDP to the outside of the tube.
The wavelength in this near-infrared range is close to the wavelength (800 nm to 1000 nm) that is employed in a remote control unit, optical communication, etc. If these devices are operated near the PDP, it is possible that a malfunction maybe caused and therefore leakage of the near-infrared ray from the PDP must be prevented.
Also, the electromagnetic radiation such as microwave, ultra low frequency radiation, etc., are generated by the operation of the PDP, and then leak out to the outside, although amount of the leakage is very small. Since the provisions for leakage of electromagnetic radiation, etc., are specified in the information device or equipment, or the like, the leakage of the electromagnetic waves must be suppressed below the specified value.
In addition, when rays of light are incident upon the display screen from the outside, the incident light is reflected by the display screen and also the contrast ratio of the screen is lowered since the display screen of the PDP is flat. Therefore, the reflection of the incident light from the outside must be suppressed.
For the purpose of satisfying these requirements, a shielding base member is arranged in front of the display screen of the PDP.
In the related art, such a shielding base member is manufactured by the method in which a plastic film to which a metal foil is adhered is pasted on the transparent glass substrate and then the metal foil is patterned, or the like. More particularly, normally the thickness of the metal foil is thin, such as about 10 xcexcm. Therefore, in order to make the handling of the metal foil easy, first the metal foil is pasted onto the plastic film. Then, in order to pattern the metal foil with good precision, the plastic film having the metal foil thereon is pasted on the glass substrate that has strong rigidity, and then the metal foil is patterned.
In the related art, because the metal foil and the plastic film are formed integrally to make the handling of the metal foil easy, if the shielding base member is manufactured using same, the plastic film remains on the shielding base member. The plastic film has low optical transmittance and high haze (degree of opaqueness), as compared with the transparent glass substrate.
Accordingly, since the plastic film remains on the shielding base member, the optical transmittance of the shielding base member is lowered and the haze (degree of opaqueness) the shielding base member is increased. As a result, there is the problem of poorer visibility of the screen of the PDP due to the shielding base member.
In order to further increase the rigidity of the plastic film on which the metal foil is pasted, there is the shielding base member in which the metal foil is pasted onto the plastic film via an adhesive layer. In the case that the plastic film is rolled up on a roller in manufacture utilizing the roll-to-roll method, etc., if the adhesive layer is pressed by foreign matter, etc., dents are readily formed occurs in the adhesive layer because the adhesive layer is soft in itself and the quality of the shielding base member is lowered.
In other related art, the shielding base member includes a plastic film having a near-infrared absorbing function. Thus, the structure of such shielding base member becomes complicated and also incorporates the plastic film. As a result, there remain the problems that the optical transmittance of the shielding base member is further lowered and that the haze (degree of opaque) is further increased.
It is an object of the present invention to provide a shielding base member with high optical transmittance and low haze (degree of opaqueness), and a method of manufacturing the same.
Also, it is another object of the present invention to provide a method of manufacturing a shielding base member having an adhesive layer without denting.
The present invention provides a shielding base member manufacturing method which comprises the steps of forming a structure, in which a first adhesive layer, a resin layer, and a metal foil are laminated sequentially on a release layer of a plastic film that has the release layer at one surface, forming a metal layer pattern by patterning the metal foil, and forming the first adhesive layer, the resin layer, and the metal layer pattern, in this order, on a transparent substrate by separating the release layer from the first adhesive layer along an interface and then pasting the first adhesive layer onto the transparent substrate.
As described above, since the handling of the metal foil that is patterned is not easy, the metal foil is pasted onto the plastic film via the resin layer and then the plastic film having the metal foil thereon is pasted onto a transparent substrate such as a glass substrate having strong rigidity. As a result, the plastic film whose optical transmittance is low and whose haze (degree of opaqueness) is high remains in the shielding base member.
The shielding base member manufacturing method of the present invention does not leave the plastic film in the shielding base member.
More particularly, first the adhesive layer, the resin layer, and the metal foil are formed on the surface of a plastic film on which a release layer is formed. Then, the metal layer pattern is formed by patterning the metal foil.
Since the metal foil is supported on the plastic film via the adhesive layer and the resin layer, the plastic film has rigidity and thus the handling of the metal foil can be facilitated. Accordingly, there is no need to form a pattern in the metal foil after this plastic film is pasted onto the transparent substrate. As a result, the roll-like plastic film onto which the metal foil is pasted is extended and then the metal foil can be patterned by the so-called roll-to-roll method.
After the release layer formed on the plastic film is separated from the first adhesive layer along the interface, the first adhesive layer, the resin layer, and the patterned metal layer are pasted onto a transparent substrate such as a glass substrate.
Thus, the shielding base member is free of a plastic film whose optical transmittance is low and whose haze is high.
As described above, according to the shielding base member manufacturing method of the present invention, the patterning of the metal foil can be carried out by the roll-to-roll method and thus the production efficiency of the shielding base member can be improved. Also, since the plastic film is not left in the shielding base member, a shielding base member whose optical transmittance is high and whose haze is low can be easily manufactured.
Also, the present invention provides a shielding base member manufacturing method which comprises the steps of forming a structure in which a first adhesive layer, a resin layer, and a metal foil are laminated in sequence, on a release layer of a plastic film, separating the release layer from the first adhesive layer along an interface and then pasting the first adhesive layer onto the transparent substrate, and forming a metal layer pattern by patterning the metal foil.
According to the present invention, first the first adhesive layer, the resin layer, and the metal layer are formed on the plastic film via the release layer, then the release layer is separated from the first adhesive layer along the interface, and then the first adhesive layer, the resin layer, and the metal layer are pasted onto the transparent substrate. Then, a metal layer pattern is formed in the metal layer on the transparent substrate.
According to the above embodiment of the shielding base member manufacturing method, the metal layer pattern is formed by patterning the metal foil, which is formed over the plastic film, by the roll-to-roll method. In contrast, according to another embodiment of the present invention, the first adhesive layer, the resin layer, and the metal layer are transferred onto the transparent substrate, and then the metal layer is patterned. Also, if a substrate having a strong rigidity such as a glass substrate, for example, is employed as the transparent substrate, stable metal layer patterns can be formed.
Also, the present invention provides a shielding base member manufacturing method which comprises the steps of preparing a first plastic film including a first adhesive layer, a resin layer, and a metal foil in sequence on a surface, forming a metal layer pattern by patterning the metal foil, forming the resin layer and metal layer pattern on a second adhesive layer of a second plastic film, which has a release layer and the second adhesive layer sequentially formed on a surface, by separating the first adhesive layer from the resin layer along an interface, then pasting a surface of the second adhesive layer of the second plastic film onto a surface of the resin layer, separating the release layer from the second adhesive layer along an interface and then pasting a surface of the second adhesive layer onto the transparent substrate.
In the present invention, first the first plastic film that has the sequence of the first adhesive layer, the resin layer, and the metal foil formed on its surface is prepared, and then the metal layer patterns are formed by patterning the metal foil. If the roll-to-roll method is employed for the purpose of improving the production efficiency, dents are easily generated in the first adhesive layer by foreign matter, or the like when the first plastic film is wound on the roll. Then, the first transfer body consisting of the resin layer and the metal layer patterns formed thereon is obtained by separating the first adhesive layer of the first plastic film from the resin layer along the interface.
Then, the second plastic film having the release layer and the second adhesive layer formed in sequence from the bottom is prepared. Then, the exposed surface of the second adhesive layer is pasted onto the surface of the resin layer, on which metal layer pattern is formed, in the first transfer body. Accordingly, the resin layer and the metal layer pattern are formed on the second adhesive layer of the second plastic film. That is, the new second adhesive layer in which the dent defect is not generated is formed under the resin layer in place of the first adhesive layer in which the dent defect is generated.
Then, the second adhesive layer is separated from the resin layer along the interface to form a second transfer sheet consisting of the second adhesive layer, the resin layer, and the metal layer pattern sequentially from the bottom. Then, the exposed surface of the second adhesive layer of this second transfer sheet is pasted onto one surface of the glass substrate to form a shielding base member that has no dents.
As described above, according to the present invention, since the plastic film does not remain in the shielding base member, a shielding base member having high optical transmittance and low haze can be easily manufactured. Also, since the metal foil is formed on the first plastic film having the first adhesive layer and high rigidity, the metal foil can be patterned by the roll-to-roll method while expanding the plastic film, and thus the production efficiency can be improved.
In addition, even if dents form in the first adhesive layer at this time, the first adhesive layer can be replaced by the new second adhesive layer in later steps. Since the roll-to-roll method is not needed in the step after the second adhesive layer is formed, the shielding base member can be manufactured without winding the second adhesive layer on the roll. Therefore, no dent is formed in the second adhesive layer of the shielding base member, and thus a shielding base member of high quality can be manufactured with high yield.
Also, the present invention provides a shielding base member manufacturing method which comprises the steps of preparing a first plastic film including a first adhesive layer, a resin layer, and a metal foil sequentially on a surface, forming a metal layer pattern by patterning the metal foil, forming a resin layer and the metal layer pattern on a second adhesive layer of a second plastic film, which has a release layer, separating the first adhesive layer from the resin layer along an interface and then pasting a surface of the second adhesive layer of the second plastic film onto a surface of the resin layer, and separating the release layer from the second adhesive layer along an interface. In this embodiment, unlike the previously described method embodiments, the shielding base member is not formed by pasting the second transfer body (the second adhesive layer, the resin layer, and the metal layer patterns) onto a transparent substrate, but the member consisting of the second adhesive layer, the resin layer, and the metal layer pattern is used as the shielding base member by exposing the surface of the second adhesive layer and pasting that exposed surface directly onto the display screen of the PDP.
The present invention also provides a shielding base member which comprises a transparent substrate, a first adhesive layer formed on the transparent substrate; a resin layer formed on the first adhesive layer, a metal layer pattern formed on the resin layer, and a reflection preventing layer formed on the metal layer pattern and the resin layer via a third adhesive layer.
The shielding base member of the present invention is the shielding base member manufactured by any of the above-described manufacturing methods. Since this shielding base member does not contain the plastic film whose optical transmittance is low and whose haze is high, the visibility of the PDP can be improved when such a shielding base member is employed as the shielding base member of the PDP.
Also, the present invention provides a shielding base member which comprises a transparent substrate, a first adhesive layer formed on the transparent substrate, a resin layer formed on the first adhesive layer and having at least a near-infrared absorbing function, a metal layer pattern formed on the resin layer, and a filter layer formed on the metal layer pattern and the resin layer via a second adhesive layer and having at least a reflection preventing function.
According to the present invention, the plastic film employed as the substrate that facilitates the handling of the metal foil does not remain in the shielding base member. The near-infrared absorbing function is provided by incorporating a pigment material, that absorbs a predetermined wavelength of the near-infrared portion of the spectrum, into the resin layer. Therefore, unlike the related art, there is no need to separately form the plastic film having the near-infrared absorbing function.